Adapted from Dinosaurs: The Very Latest Information and Hands-On Activities From the Museum of the Rockies, by Liza Charlesworth and Bonnie Sachatello-Sawyer. A Scholastic Professional Book.


1822: Mary Ann Mantell finds "Iguanodon" teeth in England. Her husband, Dr. Gideon Mantell publishes his description of them.

1841: Richard Owen coins the term "dinosaur."

1855: Ferdinand Hayden discovers the first dinosaur remains in the United States.

1858: The first dinosaur skeleton, "Hadrosaurus," is excavated in the United States and described by Joseph Leidy.

1890: Othniel Marsh and Edward Cope unearth 136 new species of dinosaurs in the Rocky Mountain region of the United states.

1902: Barnum Brown uncovers the first "Tyrannosaurs rex" specimen in Montana.

1909: Earl Douglass discovers the fossil-rich rocks that are now Dinosaur National Monument.

1922: Roy Chapman Andrews finds the first dinosaur eggs and nest ever uncovered, in the Gobi Desert.



John Ostrom describes "Deinonychus" as an active and agile animal and suggests that birds are related to dinosaurs. 

Dinosaurs are proven to have rigid tails that did not drag on the ground.



Research of thin sections of dinosaur bones suggests warm-bloodedness.

Bob Bakker and Peter Galton suggest birds and dinosaurs should be classified together as "Dinosauria."



Jack Horner and Bob Makela determine that some dinosaurs cared for their young.

"Seismosaurus" is uncovered in New Mexico by David Gillette.



Paul Serreno discovers some of the earliest-known dinosaurs.

Dinosaur fossils are found in Antarctica.